According to current estimates, in 2035 75 per cent of human energy production will be still generated by using fossil fuels. At the same time, the EIA expects a 50 per cent increase in energy demand by 2050. While the push for renewables intensifies, a major replacement of fossil fuels by baseload renewables has yet to be found.
Geothermal energy is the only form of renewable clean energy that is available 24/7. So far, its use has been limited by the fact that it is only in areas with a high tectonic and volcanic activity where the temperatures necessary for energy generation are close to the Earth’s surface. However, geothermal wells with a depth of 5-10 kilometres can unlock geothermal power on 70 per cent of Earth’s surface. This is why to solve the climate crisis in time, ultra-deep geothermal energy has to be scaled up globally in vast proportions as quickly as possible. Without the need for batteries or favourable weather to assure continuous energy production, ultra-deep geothermal can provide potentially limitless renewable energy on a sustainable basis.
Geothermal energy in Central and Eastern Europe has significant potential, mainly in Hungary, Southern and Eastern Slovakia, Eastern Austria and Northern Croatia. For instance, Slovakia has a techno-economical potential of around 5.5 gigawatts-thermal-hour (GWth). This figure considers the hydro geothermal potential of underground water reservoirs with temperatures 45-130°C with a good perspective for district heating and industrial/agricultural applications. With the employment of binary cycles, it is possible to use temperature levels around 130°C also for electricity production. The so-called Enhanced Geothermal Systems (EGS) could be utilised for electricity production as well.
The vast majority of district heating systems in CEE have been built before 1990 by the local authoritarian governments believing in central planning. Today they are incrementally shifting from the use of fossil fuels, mainly to burning biomass, which is the closest renewable source to existing coal/gas use. However, the use of biomass in replacing fossil fuels has to be limited to avoid negative impacts on the environment and the carbon footprint caused by its transport. Geothermal district heating could be a clean alternative. It can utilise existing heat grids without having any social disadvantages after commissioning, like flue gases, trucks/trains delivering fuel and so on.
While the decreasing cost of solar and wind energy installations has made them very attractive it is important to stress that geothermal can be very competitive. For solar or wind installed capacity, a factor of 4 or 5 has to be used to reach the same kilowatt-hours as for installed geothermal energy. Also, these renewable energy sources need either fossil fuel back-up or battery storage to be truly reliable. That usually doubles the original solar/wind cost and increases the environmental footprint. In this respect solar and wind are similar to nuclear: it also seems to be a very cheap source of energy, but when you add the hidden costs like security and decommissioning, it becomes one of the most expensive.
In contrast, geothermal is by definition a baseload and dispatchable source of energy available 24/7/365 and independent of the weather conditions. This is why – when considering all hidden costs properly – geothermal is already today on the same level of the Levelised cost of generated electricity with solar and wind. For continuous energy source on-demand, geothermal energy is the most competitive and economical renewable source, equally during winter or in the night.
The speed of deployment of geothermal energy in Central and Eastern European countries can make a huge difference in the transition from fossil fuels. If they act now, they could skip using gas as an interim energy source and go straight from coal to renewables. Usually, it takes 4-5 years from planning to commissioning. To fulfil climate targets, it is crucial to start working on a larger number of geothermal projects as soon as possible to reduce the time necessary for shifting from natural gas.
If CEE governments prioritise geothermal energy, cut the administrative red tape and set up financial schemes to support the exploration phase of geothermal projects then the region could soon become a beacon to the world searching for clean energy.